1. Field of the Invention
The present invention relates to an improvement of a supporting platform on which a person or a thing is to be placed, such as a chair, table, or working stand.
2. Description of the Prior Art
Among such supporting stands as a chair whose height is adjustable, as described above, there are many types which are provided with a slide section, by which the height in the vertical direction is variable, at the column between the base of a chair and platform thereof.
In the case of a height adjustable chair having such a slide section as described above, since the slide section is made of friction components, there is a shortcoming by which the wearing thereof proceeds to cause the service life thereof to be comparatively shortened, due to the application of a person's weight.